What is SERA? By preclean do you mean the microetch before hot air? ______________________________ Reply Separator _________________________________ Subject: Re: Solder Mask Residue Author: [log in to unmask] at corp Date: 7/15/97 7:26 AM Hello Mr. Lee We have seen a similar problem in different PCB shops. The problem is that the soldermask reacts with the copper surface (oxides) and forms the "shield" during the baking. It is possible to analyze the copper surface by SERA technique prior to the HASL operation. If the instrument detects the soldermask residue, it means that your precleaning operation is not sufficient enough. If you have more questions about analysis, please let me know. Best regards Michael Pavlov ECI Technology 1 Madison st. E. Rutherford, NJ 07011 (201) 773-8686 *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * *************************************************************************** *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************